Adds a given vector (array) to another one. Every element of the second array (missing element is treated to be zero) is added to the corresponding el

Add the value to the HashSet given by map.get(key), creating a new HashSet if the HashSet is null

If the string passed in is not blank or null and did not end with the trailing value, then appended the trailing value to it and return the result

将数组转为 List

一维数组转为二维数组，width表示列数，height表示行数

Converts from an int array to an Integer array.

Calculate and return the average of the two values rounded DOWN.

Decode base64 string to bytes

十进制数值减法，字符串表示每一个数

Convert a boolean value into a string.

convert byte array to a hex string

将byte数组转化为16进制字符串

计算 C2 = M xor t

Convert an arbitrary text encoding to its canonical name

Parses character set name to Charset object

Verifies that the given array is not null or empty.

Add two integers, checking for overflow.

Check if #MIN_VALUE <= value <= #MAX_VALUE and if not an IllegalArgumentException is thrown.

检验用户名是否合法，只能包括a-z,A-Z,0-9和下划线_，不能以下划线结尾 用户名有最小长度和最大长度限制，比如用户名必须是4-20位

括号匹配检测.

Clear the given calendar, setting to zero all time values less than or equal to that of the given field. For example, clearing to Calendar#HOUR will f

Take a collection of Strings and return a combined string as a comma separated list with 'and' between the final pair. For example: [a, b, c] to \"a,

Calculates combinatorial number C(n,m).

Compares the two specified double values,return 1 if the first value is greater than the second value,-1 if the first value is less than the second va

Concatenate two arrays of T type

Convert the text '&' mnemonic string to text string. The '&' symbol is treated as the mnemonic pointer. The double "&&" symbols are treated as the sin

Create a copy of the Integer array

Copy a file from source path to destination path

Compute the CRC32 of an array of bytes.

Create and returns a HttpURLConnection connection to a webpage

Creates a padding string of a certain length

返回当月开始时间

将 Date 类型转为时间字符串，格式为 format

Debug helper function that returns the diff of two property maps, only displaying the key that is different and in which map it exists compared to the

Returns the distance for the two given point

随机抽取指定数量的用户，作为中奖用户

Calculate the elapsed time between two times specified in milliseconds.